Coronosaurus Temporal range: Late Cretaceous, | |
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Skull cast | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Neornithischia |
Clade: | † Ceratopsia |
Family: | † Ceratopsidae |
Subfamily: | † Centrosaurinae |
Tribe: | † Centrosaurini |
Genus: | † Coronosaurus Ryan, Evans & Shepherd, 2012 |
Type species | |
†Centrosaurus brinkmani (Ryan & Russell, 2005) | |
Synonyms | |
Centrosaurus brinkmani |
Coronosaurus is a genus of centrosaurine ceratopsian dinosaurs which lived in the Late Cretaceous, in the middle Campanian stage. Its remains, two bone beds, were discovered by Phillip J. Currie in the Oldman Formation of Alberta, Canada, and its type and only species, Coronosaurus brinkmani, was first described in 2005, as a new species within the genus Centrosaurus . Later studies questioned the presence of a direct relationship, and in 2012 it was named as a separate genus. Coronosaurus means "crowned lizard", coming from "corona", Latin for crown, and "sauros", Greek for lizard; this name refers to the unique, crown-like shape of the horns on the top of its frill. [1] [2]
Like other ceratopsids, Coronosaurus had a large frill and horns on its head. These include a small pair of brow horns over its eyes, a large nasal horn on its snout, and, unique among ceratopsians, irregular, spiky bone masses on its frill. [1] Growing up to around 5 metres (16 ft) long and 2 tonnes (2.0 long tons; 2.2 short tons) in weight, it was mid-sized for its kind. [3] The genus is classified as a member of the Centrosaurini, a group of derived centrosaurines which has also been found include taxa such as Styracosaurus , Spinops , Rubeosaurus , and Centrosaurus , the genus it was originally placed within. [4]
Coronosaurus is known from two bone beds, BB 138 and MRR BB, located in the upper unit of the Oldman Formation, of the Belly River Group, excavated by Philip Currie between 1996 and 2000. [5] Most of the ceratopsid material, if not all, from BB 138 in Dinosaur Provincial Park, Alberta, and the MRR BB near Warner, Alberta, was referred to C. brinkmani. Bone bed 138 is located approximately fifty kilometres (31 miles) from Brooks, Alberta, in the Oldman Formation and 14.6 metres (48 ft) below the contact with the Dinosaur Park Formation. The MRR BB located approximately one hundred and eighty kilometres (110 miles) southwest of BB 138, is also from the Oldman Formation. These bone beds date to the middle Campanian stage of the Late Cretaceous period. [1] Both the specimens and the precise localities are archived at the Royal Tyrrell Museum of Palaeontology, in Drumheller, Alberta.
Michael J. Ryan and Anthony P. Russell described and named the type species, then as Centrosaurus brinkmani, in 2005. Later studies, however, did not recover a monophyletic clade with the genus' type species Centrosaurus apertus in phylogenetic analyses. Due to this, Ryan, David C. Evans and Kieran M. Shepherd erected the genus Coronosaurus for the species in 2012. The generic name is derived from the Latin corona, meaning "crown" in reference to the multiple occurrences of extra epiparietals that cover the posterior margin of its parietal, giving it a crown-like appearance, and saurus (Latinized from Greek sauros), meaning "lizard". [1] The specific name brinkmani honors Donald Brinkman, for his research in palaeoecology of the Late Cretaceous environments of Alberta. [2] In 2020, in response to the COVID-19 pandemic, Ryan was asked about the naming of the dinosaur, and stated he came up with it because its frill ornamentation made him think of the corona of the sun. He also stated his fellow students at the time had jokingly called it ‘broccoli-ceratops’. [6]
The holotype of Coronosaurus is TMP 2002.68.1. It is a large adult-sized parietal with an almost complete midline bar and a partial posterior bar with left P1–P3 processes and the partially eroded right P1-P2. The specimen lacks the extreme anterior margin of the midline bar that forms the posterior wall of the frontal fontanelle and the paper-thin lateral margins that define the medial margins of the supraorbital foramina. Other significant specimens according to Ryan & Russell (2005) include TMP 2002.68.3 (a parietal), TMP 2002.68.10 (a postorbital), and TMP 2002.68.5 (supraorbitals). [1] [2]
Coronosaurus is a medium-sized centrosaurine ceratopsid. Gregory S. Paul in 2010 estimated its body length at 5 metres (16 ft) and its weight at 2 tonnes (2.0 long tons; 2.2 short tons). [3] It had as an adult inflated supraorbital horncores — the "brow horns" above the eye sockets — but not elongated as in Zuniceratops , chasmosaurines, and more basal centrosaurines (like Albertaceratops and Diabloceratops ), that project laterally (to the sides) over the orbit. As a sub-adult its postorbital horncores are pyramidal in shape with a slight lateral inflection of the distal, upper, one half. [1]
Uniquely among ceratopsians, Coronosaurus possesses a number of accessory epiparietal ossifications rear parietal frill of the skull that fuse to the posterior and dorsal frill surface. They develop through ontogeny, the growth of the individual, as short spines that may fuse along their adjacent margins into larger, irregular bone masses. They are located close to the midline of the frill in a closely packed bunch above the base of the first epiparietal (P1), the bone spur that at each side growths downwards over the large opening in each frill half. They contribute to the substance of P1 and, through fusion, form a composite epiparietal, that is equivalent to the second epiparietal (P2) normally formed in a more lateral position. The P1 bases can thus be considered the growth positions of the second epiparietals, the P2 loci. Coronosaurus has also a uniquely shaped P3 epiparietal. It is variably developed as a short tongue-like hook or tapered spike that is oriented dorsolaterally, following the curve of the frill. [1]
Otherwise, as far as is known Coronosaurus resembles its relatives Centrosaurus and Styracosaurus in its morphology. For example, the nasal of Coronosaurus closely resembles that of Centrosaurus apertus in its unfused juvenile or subadult and fused adult forms and appears to have undergone a similar ontogenetic changes. Its erect, laterally compressed nasal horn core has a blunt tip that is formed from the fusion of the opposing nasals. It sits over the posterior portion of the external nares, as it does in all centrosaurines. All juvenile and most adult specimens have gently recurved anterior and posterior margins resulting in most horns having an apex that is oriented at least slightly caudally (backwards). [2]
In its original description, Ryan & Russell (2005) considered Coronosaurus to represent a new species of Centrosaurus on the basis of a small phylogenetic analysis. It included seventeen characters and nine taxa. Coronosaurus (as Centrosaurus brinkmani) and C. apertus grouped at the base of the Centrosaurinae, while Styracosaurus was found to be more closely related to Pachyrhinosaurus , and other derived centrosaurines, than to Centrosaurus. In 2011, Anthony R. Fiorillo and Ronald S. Tykoski modified the analysis of Currie et al. (2008), with 54 characters, to include more taxa, such as C. brinkmani. They found C. brinkmani to be the sister taxon of the clade of Styracosaurus and C. apertus, while Pachyrhinosaurus and other derived centrosaurines were in a separate lineage. Thus, this analysis found no support for the monophyly of Centrosaurus. [7]
Later, Farke et al. (2011) used 97 morphological characters to assess the phylogenetic position of a new taxon which they named Spinops . Spinops was found to be in a polytomy with Centrosaurus apertus, C. brinkmani and Styracosaurus, and therefore C. brinkmani was excluded from the analysis to increase the resolution. [8] Finally, Ryan, Evans & Shepherd (2012) used the data matrix of Farke et al. (2011) to assess the phylogenetic position of Xenoceratops . Their revised analysis had significantly better resolution than that presented by Farke et al. (2011), due in part to the additional scoring of missing characters for some taxa based on direct observation of their specimens. For example, five additional characters were scored for C. brinkmani. In the resultant tree, it was found to be in more advanced position than Spinops and C. apertus, as the sister taxon of Styracosaurus. Thus the new generic name, Coronosaurus, was given to it. [4] The cladogram presented below follows a phylogenetic analysis by Chiba et al. (2017): [9]
Centrosaurinae |
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Studies suggest that the paleoenvironment of the Oldman Formation was an ancient coastal plain. [10] In addition to remains of Coronosaurus, this formation has produced the remains of the theropods Saurornitholestes , Daspletosaurus , Troodon , Dromaeosaurus and Hesperonychus , the ceratopsids Albertaceratops , Chasmosaurus , and Anchiceratops , the hadrosaurids Brachylophosaurus , Gryposaurus , Parasaurolophus , and Corythosaurus , the thescelosaurid Albertadromeus and the ankylosaurid Scolosaurus .
Ceratopsidae is a family of ceratopsian dinosaurs including Triceratops, Centrosaurus, and Styracosaurus. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are known from western North America, which formed the island continent of Laramidia during most of the Late Cretaceous. Ceratopsids are characterized by beaks, rows of shearing teeth in the back of the jaw, elaborate nasal horns, and a thin parietal-squamosal shelf that extends back and up into a frill. The group is divided into two subfamilies—Chasmosaurinae and Centrosaurinae. The chasmosaurines are generally characterized by long, triangular frills and well-developed brow horns. The centrosaurines had well-developed nasal horns or nasal bosses, shorter and more rectangular frills, and elaborate spines on the back of the frill.
Styracosaurus is an extinct genus of herbivorous ceratopsian dinosaur from the Late Cretaceous of North America. It had four to six long parietal spikes extending from its neck frill, a smaller jugal horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to 60 centimeters long and 15 centimeters wide. The function or functions of the horns and frills have been debated for many years.
Einiosaurus is a genus of herbivorous centrosaurine ceratopsian dinosaur from the Upper Cretaceous of northwestern Montana. The name means 'bison lizard', in a combination of Blackfeet Indian eini and Latinized Ancient Greek sauros; the specific name (procurvicornis) means 'with a forward-curving horn' in Latin. Einiosaurus is medium-sized with an estimated body length at 4.5 metres (15 ft).
Achelousaurus is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 74.2 million years ago. The first fossils of Achelousaurus were collected in Montana in 1987, by a team led by Jack Horner, with more finds made in 1989. In 1994, Achelousaurus horneri was described and named by Scott D. Sampson; the generic name means "Achelous lizard", in reference to the Greek deity Achelous, and the specific name refers to Horner. The genus is known from a few specimens consisting mainly of skull material from individuals, ranging from juveniles to adults.
Centrosaurus is a genus of centrosaurine ceratopsian dinosaur from Campanian age of Late Cretaceous Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago.
Monoclonius is an extinct genus of herbivorous ceratopsian dinosaur found in the Late Cretaceous layers of the Judith River Formation in Montana, United States, and the uppermost rock layers of the Dinosaur Park Formation in Alberta, Canada dated to between 75 and 74.6 million years ago.
Medusaceratops is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Judith River Formation of Montana, northern United States. It contains a single species, Medusaceratops lokii.
Albertaceratops was a genus of centrosaurine horned dinosaur from the middle Campanian-age Upper Cretaceous Oldman Formation of Alberta, Canada.
Centrosaurinae is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia but isolated taxa have been found in China and Utah as well.
Kosmoceratops is a genus of ceratopsid dinosaur that lived in North America about 76–75.9 million years ago during the Late Cretaceous period. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument in 2006 and 2007, including an adult skull and postcranial skeleton and partial subadults. In 2010, the adult was made the holotype of the new genus and species Kosmoceratops richardsoni; the generic name means "ornate horned face", and the specific name honors Scott Richardson, who found the specimens. The find was part of a spate of ceratopsian discoveries in the early 21st century, and Kosmoceratops was considered significant due to its elaborate skull ornamentation.
Nasutoceratops is genus of ceratopsid dinosaur that lived in North America during the Late Cretaceous period, about 76.0–75.5 million years ago. The first known specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument (GSENM) from 2006 onwards, including a subadult skull with a partial postcranial skeleton and rare skin impressions and two other partial skulls. In 2013, the subadult was made the holotype of the new genus and species Nasutoceratops titusi; the generic name means "large-nosed horned face", and the specific name honors the paleontologist Alan L. Titus for his work at the GSENM. The dinosaur was noted for its large nose in news reports, and later featured in Jurassic World films.
Spinops is an extinct genus of centrosaurine ceratopsian dinosaur from the Late Cretaceous of Alberta, southern Canada. It was a medium-sized ceratopsian, reaching 4.5 metres (15 ft) in length and 1.3 metric tons in body mass.
Xenoceratops is a genus of centrosaurine ceratopsid dinosaur known from the Late Cretaceous, and is known to have lived in what is currently Alberta, Canada. The genus has one known species, Xenoceratops foremostensis. Its remains were discovered in the Foremost Formation.
Mercuriceratops is an extinct genus of herbivorous chasmosaurine ceratopsid dinosaur known from the Late Cretaceous of Alberta, Canada and Montana, United States. It contains a single species, Mercuriceratops gemini.
This timeline of ceratopsian research is a chronological listing of events in the history of paleontology focused on the ceratopsians, a group of herbivorous marginocephalian dinosaurs that evolved parrot-like beaks, bony frills, and, later, spectacular horns. The first scientifically documented ceratopsian fossils were described by Edward Drinker Cope starting in the 1870s; however, the remains were poorly preserved and their true nature was not recognized. Over the next several decades, Cope named several such genera and species. Cope's hated rival, Othniel Charles Marsh, also described ceratopsian remains. In 1887, Marsh mistook a Triceratops horn for one belonging to a new species of prehistoric Bison. Marsh also named the eponymous genus Ceratops in 1888. The next year, he named the most famous ceratopsian, Triceratops horridus. It was the discovery of Triceratops that illuminated the ceratopsian body plan, and he formally named the Ceratopsia in 1890.
Regaliceratops is a monospecific genus of chasmosaurine ceratopsid dinosaur from Alberta, Canada that lived during the Late Cretaceous in what is now the St. Mary River Formation. The type and only species, Regaliceratops peterhewsi, is known only from an adult individual with a nearly complete skull lacking the lower jaw, which was nicknamed "Hellboy". Regaliceratops was named in 2015 by Caleb M. Brown and Donald M. Henderson. Regaliceratops has an estimated length of 5 metres (16 ft) and body mass of 2 metric tons. The skull of Regaliceratops displays features more similar to centrosaurines, which suggests convergent evolution in display morphology in ceratopsids.
Wendiceratops is a genus of herbivorous centrosaurine ceratopsian dinosaur from the Late Cretaceous of Canada.
Yehuecauhceratops is a genus of horned centrosaurine ceratopsid dinosaur from the Late Cretaceous of Coahuila, Mexico. It contains a single species, Y. mudei, described from two partial specimens by Rivera-Sylva et al. in 2016 and formally named by Rivera-Sylva et al. in 2017. It was a small centrosaurine with a body length of 3 metres (9.8 ft), making it smaller than Agujaceratops and Coahuilaceratops, the other two ceratopsids in its environment; the three may have been ecologically segregated. A ridge bearing a single roughened projection near the bottom of the squamosal bone, which probably supported a small horn, allows Yehuecauhceratops to be distinguished from other centrosaurines. Its affinities to nasutoceratopsin centrosaurines, such as Avaceratops and Nasutoceratops, are supported by various morphological similarities to the former.
Stellasaurus is a genus of centrosaurine ceratopsid dinosaur that lived in Montana during the Late Cretaceous. The type and only species is Stellasaurus ancellae. Its remains have been found in the Late Campanian age Two Medicine Formation, the same geological unit which its relatives Rubeosaurus, Einiosaurus, and Achelousaurus were discovered in.